Tapered vacuum nozzle for anchor-bolt retrofits
I frequently drill holes in concrete foundations for seismic anchors, such as all-thread bolts. The bolts are bonded to the concrete with epoxy, which means the holes that I drill have to be thoroughly cleaned for the epoxy to get a proper grip. I used to blow the dust out of the holes with compressed air, but that technique makes a mess and poses a danger to lungs and eyes. So I’ve switched to a better method.
As shown in the drawing, I made a simple nozzle out of copper plumbing fittings for my shop vacuum. The series of copper reducers steps down to an 8-in. long piece of 1/2-in. copper pipe, which is small enough in diameter to fit inside the 3/4-in. dia. holes in the concrete. And just for the fun of it, if you like horns, the nozzle sounds pretty good when blown through the 1/2-in. dia. end.
Randi Dickson, Oakland, CA